Polyvinyltrialkylsilanes are known to have a selective gas-permeability (cf. French Pat. No. 1,567,175, Int. Cl. B 01 d 53/22). However, despite a high selectivity, these polymers have an insufficient gas-permeability, for example relative to oxygen P.sub.O.sbsb.2 =4.45.times.10.sup.-9 cm.sup.3 cm/cm.sup.2 .multidot.cm Hg.multidot.sec). These polymers are produced by polymerization of vinyltrialkylsilanes in the presence of organolithium compounds (cf. USSR Inventor's Certificates Nos. 162,531 and 295,435, Int. Cl. C 08 f 130/08).
Known in the art are also polymers based on hexaorganocyclotrisiloxanes possessing high total gas-permeability. However, in certain cases these polymers have a low selectivity, for example with a gas mixture of oxygen and nitrogen (P.sub.O.sbsb.2 /P.sub.N.sbsb.2 =2.0-2.2).
It is an object of the present invention to provide block-copolymers of vinyltrialkylsilanes-hexaorganocyclotrisiloxanes which have high total gas-permeability and high selectivity.
It is another object of the present invention to provide a method for producing block-copolymers of vinyltrialkylsilanes-hexaorganocyclotrisiloxanes.